Here in CA I haven't noticed gains or losses for KOA. I've found some of them very nice and a few of them overpriced with less than perfect maintenance. I pull up the review sites and if the KOA gets the best ratings in area and it is halfway reasonable, I'll do it. I'm not wedded to them but they're not an automatic no either. I'm usually passing through for the night and I don't get any of their ala carte extras. Just basic water/electric site.
Example of a nice one: Richfield UT. Was there a couple weeks ago. Lots of shade trees, grass, attractive grounds. Pool looked good, clean bathrooms.
There's another one fairly local to me which will remain nameless. I actually like the place in a funky sort of way. Kind of throwback to rustic western campgrounds in the past. But geez, at $50. per night maybe break out some paint cans, and throw in a few trips to Home Depot.